Vacuum enclosure for confining and removing debris produced by tool operation

ABSTRACT

An enclosure cooperates with a vacuum source to confine and remove debris produced by operation of tools on workpieces. The enclosure comprises a housing and a work plate that defines the bottom of a work chamber in the housing and a work surface where tools and workpieces can be placed. A vacuum chamber is formed against a lower surface of the work plate, and the work plate has an extensive array of holes that place the work chamber in communication with vacuum chamber. A vacuum source coupled to the vacuum chamber draws air flows through holes in the work plate that remove debris in the work chamber. A window permits viewing of the interior of the work chamber, and an access port permits a worker to insert his hands into the work chamber to handle workpieces or operate tools.

FIELD OF THE INVENTION

The invention relates to enclosure for confining and removing debris created by the operation of power and hand tools upon workpieces, and more specifically, to an enclosure in which suction is used more effectively to remove debris.

DESCRIPTION OF THE PRIOR ART

Power tools, such as a grinder, sander, and arc welder, produce particulate debris and often noxious fumes. Particulate debris poses an immediate risk eye injury and often necessitates the use of goggles or other protective eyewear. As well, debris produced by a grinder or sander can scatter widely about a work area, making clean-up tedious and time-consuming.

The prior art has suggested enclosures that cooperate with a vacuum source to manage debris and fumes produced by operation of power tools and the like. Closed environments may be created around tools and workpieces using rigid or flexible enclosures. Special openings may be provided to permit hand access while preventing any significant scattering of flying debris. A vacuum line may be coupled to the interior of the enclosure to remove air borne contaminants. As well, a movable suction head may be provided in the enclosure to allow a worker to remove particulate debris otherwise accumulating in the interior. Examples of such practices are found in U.S. Pat. No. 1,977,386 to Holes; U.S. Pat. No. 4,813,462 to Linn; U.S. Pat. No. 4,928,348 to Clayton; and, U.S. Pat. No. 5,295,771 to Wehrmann et al.

Although the prior practices are useful, it would be desirable to provide a vacuum enclosure that not only removes fumes and airborne contaminants but also continually removes particulate debris continuously and effectively during power tool operation without frequent intervention by a worker.

SUMMARY OF THE INVENTION

In one aspect, the invention provides an enclosure that cooperates with a vacuum source to confine and remove debris produced when a tool operates on a workpiece. The enclosure comprises a housing that cooperates with a work plate to define a work chamber. The work plate has an upper work surface that defines the bottom of the work chamber and serves to support tools and workpieces. A window permits viewing into the work chamber, and a hand access port permits manual manipulation of tools and workpieces within the work chamber. A vacuum chamber is formed against a lower surface of the work plate, and the work plate is formed with a multiplicity of holes that place the vacuum chamber in communication with the work chamber. The holes are preferably distributed to span most of the work surface so as to distribute suction and entraining air flows about the work plate. The vacuum source may be remote from the enclosure and coupled to the vacuum chamber with a pressure line, but the source is preferably mounted in the enclosure itself to provide an entirely self-contained unit. In a preferred form, a filtering mechanism is installed in the vacuum chamber to remove debris from entraining air flows, and the debris is allowed to deposit in a tray that can be removed from the housing for cleaning.

Other aspects of the invention will be apparent from a description below of a preferred embodiment, and will be more specifically defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to drawings illustrating a preferred embodiment, in which:

FIG. 1 is a perspective view of a vacuum enclosure;

FIG. 2 is a front view of the vacuum enclosure;

FIG. 3 is a left side view of the vacuum enclosure;

FIG. 4 is a sectional view along lines 4-4 of FIG. 3;

FIG. 5 is a sectional view along lines 5-5 of FIG. 4; and,

FIG. 6 is a fragmented sectional view along lines 6-6 of FIG. 5.

DESCRIPTION OF PREFERRED EMBODIMENT

An overview of principal components of a vacuum enclosure embodying the invention will be provided with reference to FIGS. 1 and 5.

The enclosure includes a housing 10 formed of wood panels. The housing 10 has a left side wall 12, a right side wall 13, a rear wall 14, a bottom wall 15, a front wall formed as lower and upper sections, spaced-apart 16, 26, and a top wall 28. A wood work plate 30 cooperates with the housing 10 to define a work chamber 22 within the housing 10. The work plate 30 has an upper work surface that defines the bottom of the work chamber 22 and supports tools or workpieces placed in the work chamber 22. A light 90 mounted to the rear housing wall 14 illuminates the work chamber 22, and a shielded window 11 permits viewing into the work chamber 22 during tool operation and workpiece handling. The window 11 is simply a rigid transparent sheet of plastic fastened with screws (only one screw 24 specifically identified in FIG. 1) to top wall 28 of the housing 10.

A removable wood door 17 permits access to the interior of the housing 10 for insertion or removal of the work plate 30 and a metal tray 45 used to collect debris. A hand access port 80 in the door 17 is normally used to transfer items such as tools or workpieces to and from the work chamber 22 or to reach into the work chamber 22 to handle objects or operate tools. A vacuum chamber 23 is formed against a lower surface of the work plate 30, and the work plate 30 is extensively apertured to place the work chamber 22 in communication with the vacuum chamber 23. A suction or vacuum pump 70 is coupled to the vacuum chamber 23, draws air through the work plate 30, and entrains debris from the work chamber 22 into the vacuum chamber 23. In the vacuum chamber 23, a filtering mechanism separates debris from entraining air flows, and the debris deposits in the tray 45.

The removable front door 17 is apparent in FIGS. 1-3. The door 17 seats in a space between the lower and upper front wall sections 16, 26. A handle 27 fastened to the door can be gripped to facilitate installation or removal of the door 17. The lower edge of the door 17 is overlapped by a steel retaining bar 18 fastened with screws to the lower front wall section 16. The upper edge of the door 17 is held with a conventional latch 19 that rotates on the upper front wall section 26 to release or secure the door 17. The door 17 may alternatively be hinged to the housing 10 for pivoting between open and closed orientations.

The hand access port 80 is apparent in FIGS. 1-3. The access port 80 includes a rectangular opening (not separately indicated) formed in the door 17 and dimensioned to pass a worker's hands. Such dimensioning also allows tools or workpieces to be inserted into the work chamber 22 without requiring removal of the front door 17 itself. The hand access port 80 also includes a closure or obstructing mechanism consisting of upper and lower flaps fastened to the housing 10 with staples, adhesives or other conventional fasteners. The flaps 85 are formed of rubber and biased by inherent elasticity to the rest orientation shown in FIGS. 1 and 2. In that orientation, the flaps 85 are coplanar with the opening of the port 80 and free edges of the flaps 85 mate along a horizontal line of contact 86, obstructing the opening almost completely against escape of debris. The flaps are free to deflect from a fully closed position on contact with a worker's hand, tools, workpieces or power cords but still significantly reduce the amount of debris that can escape. The flaps also permit ambient air to flow into the work chamber 22 in response to operation of the vacuum pump 70 but a small venting hole may be formed in the housing 10 if required. Other closure/obstruction mechanism may be used. For example, a single elastic flap may be installed and need not obstruct the opening completely. Other alternatives include use of cloth strips or a vinyl sheet over the access port 80.

The work plate 30 is shown in FIGS. 1, 4 and 5. The work plate 30 is generally rectangular and dimensioned to conform to internal dimensions of the housing 10 (as most apparent in FIG. 4). Near the back of the housing 10, the work plate 30 rests on triangular wood rackets 31 fastened to corners of the housing 10. Near the front of the housing 10, an elongate wood spacer 32, fastened to the lower surface of the work plate 30 with screws 36, bears against a wood plate 52 (apparent only in FIG. 5 and described more fully below). The work plate 30 can consequently be freely removed through the door 17 for repair or replacement. A principal alternative is to support the work plate 30 solely with posts or spacers fastened to the bottom of the work plate 30 and positioned to bear against the debris tray 45.

The vacuum chamber 23 is most apparent in FIG. 5. The lower surface of the work plate 30 defines the upper boundary of the vacuum chamber 23, and a lower horizontal wood plate defines the lower boundary of the vacuum chamber 23. The housing side walls 12, 13 close opposing side edges of the vacuum chamber 23, as apparent in FIG. 5. The forward and rear walls close forward and rear edges of the vacuum chamber 23 in a similar manner (not shown). The suction pump 70 is mounted to the bottom of the lower plate 52 and draws air through a circular hole 53 centered in the lower plate 52 and functioning as a suction inlet port 80 of the vacuum chamber 23. The suction pump 70 expels air through a pipe 65 that extends through a clearance hole 66 in the left housing wall 12. As mentioned above, the suction source may be remote from the enclosure and coupled to the suction inlet port 53 with a bose.

The debris tray 45 is located within the vacuum chamber 23 as apparent in FIG. 5. The tray 45 has a flat rectangular bottom that seats on the lower horizontal plate 52 associated with the vacuum chamber 23. The tray 45 also has a rectangular side wall whose opposing left and right wall sections 51 are apparent in FIG. 5. The left housing wall 12, the right housing wall 13 and the rear housing wall 14 have a composite construction, each comprising an outer wood panel 20 and an inner wood panel 21, glued or otherwise secured to one another. This arrangement (which is not critical) permits parallel horizontal grooves 46 to be formed in interior surfaces of the housing side walls 12, 13 without routering. The grooves 46 receive the opposing wall sections 51 of the tray 45 in relative sliding relationship, permitting extraction of the tray 45 when the front door 17 is removed. A similar horizontal groove is formed in the rear wall 14 of the housing 10 to partially receive the side wall of the tray 45 ensuring that debris at the rear of the work chamber 22 falls properly into the tray 45. The debris tray 45 has a central flow hole 55 in which a short vertical length of metal tube 56 is installed. The hole aligns vertically with the inlet bole or port 53 of the vacuum chamber 23. This arrangement prevents the presence of the tray 45 in the vacuum, chamber 23 from obstructing air flows through the suction inlet port 53.

The filtering assembly is illustrated in FIGS. 5 and 6. The assembly includes a filter support 120 with a flat base and a downwardly extending cylindrical side wall 123 (indicated in FIG. 6), and a cylindrical filter 125 formed from conventional porous filtering material. The filter support 120 is fastened with screws 122 to the lower surface of the work plate 56, and the cylindrical filter 125 surrounds and elastically grips the filter support 120. The side wall 123 of the filter support 120 has a multiplicity of vertical slots (such as the slot 121 specifically identified in FIG. 6) equally spaced circumferentially to permit air to be drawn through the filter 125 into the interior of the filter support 120. The filter support 120 simply rests on the tray 45 below, and the filtering assembly is consequently removed together with the work plate 30 when the front door 17 of the housing 10 is removed.

The aperturing of the work plate 30 is most apparent in FIG. 4. A central rectangular area 35 (indicated in phantom outline) has no apertures, which accommodates the mounting of the filter support 120 and the cylindrical filter 125 against the lower surface of the work plate 30. Horizontally outward of the central area 35, the work plate 30 has multiple holes 34 arranged in a regular array of rows and columns and spanning most of the upper surface of the work plate 30. The holes 34 may be countersunk to further encourage debris to fall into the holes 34 for entrainment into the vacuum chamber 23. The left, right, and rear edges of the work plate 30 are formed with elongate recesses that cooperates with the housing walls to define three slots 33 through which suction can draw debris into the vacuum chamber. This encourages removal of debris that would otherwise accumulate at lower edges of the work chamber 22.

Electric power required for operation of the enclosure is supplied with power cords collectively indicated in FIG. 3 with reference number 71. A principal power cord 72 can be plugged into a conventional AC line source (not shown). A manually-operated switch 145 receives AC power along the power cord 72. In an ON position, the switch 145 supplies power to the vacuum pump 70 along a power cord 73 that extends into the housing 10 through a lower clearance hole 25 formed in the rear housing wall 14. The switch 145 simultaneously supplies power to the light 90 along another power cord 74 that extends into the housing 10 through an upper clearance hole 91 in the rear housing wall 14.

A significant advantage is that the work plate 30 with its extensive array of holes 34 cooperates with the vacuum chamber 23 to distribute suction about the work surface and effectively remove debris that settles on the work surface. As well, the slots 33 remove debris that would otherwise lodge at the base of chamber walls. Within practical limits, the work chamber may be self-cleaning.

Other changes can be made to the enclosure of FIGS. 1-5. In the enclosure above, the holes 34 of the work plate 30 serve as the primary means for directing suction into the work chamber 22, and the slots or gaps 33 at the periphery of the work plate 30 are secondary. If the work plate 30 is supported directly from the debris tray 45 or the lower plate 52 with spacers such as cylindrical posts inset from corners of the work plate, the corner brackets 31 and elongate spacer 32 can be eliminated, leaving the perimeter of the work chamber 22 unobstructed. The work plate 30 can then be dimensioned and shaped to define a continuous gap between edges of the work plate 30 and interior surfaces of the work chamber, which may be expanded to accommodate larger air flows. The gap then functions as the primary means of directing suction into the work chamber 22. This arrangement enhances the collection and entrainment of debris along edges of the work chamber 22. The general configuration of an enclosure embodying such changes is shown in FIGS. 7 and 8.

Various materials and fabricating techniques may be substituted for those described. The housing 10 is preferably formed of wood to reduce cost and weight. A steel or plastic construction might be adopted but such materials might require milling, welding, molding of grooves, or provision of more complex and expensive joints between panels. With a steel construction, the housing 10 may be unduly heavy or unduly flimsy if thin metal sheet is used. The work plate 30 is expect to be scored or otherwise damaged, for example during grinding operations, and trying to protect its upper surface may be impractical and not conducive to quick use of tools. For such reasons, the work plate 30 is preferably formed of wood, once again light, inexpensive and easily replaced. Other material substitutions should be apparent to those skilled in the fabrication art. Also, the enclosure may be dimensioned and shaped to enclose larger pieces of machinery, such as drill presses.

It will be appreciated that a particular embodiment of the invention has been described together with suggested modifications and that further modifications may be made without necessarily departing from the scope of the appended claims. 

1. An enclosure cooperating with a vacuum source to confine and remove debris produced by operation of a tool on a workpiece, the enclosure comprising: a housing; a work plate mounted in the housing, the plate cooperating with the housing to define a work chamber above the work plate, the work plate comprising an upper work surface for supporting the tool and the workpiece; a window attached to the housing and permitting viewing into the work chamber; an access port attached to the housing and shaped to permit manual manipulation of the tool and the workpiece in the work chamber; and, means cooperating with the work plate to define a vacuum chamber against a lower surface of the work plate, the vacuum chamber comprising an inlet port for coupling the vacuum chamber to the vacuum source, the work plate comprising a multiplicity of holes extending between its upper and lower surfaces that place the vacuum chamber in communication with the work chamber, the passages positioned to distribute vacuum within the vacuum chamber about the work surface.
 2. The enclosure of claim 1 comprising a filter located within the vacuum chamber and shaped to enclose the inlet port against entrainment of debris from the vacuum chamber to the vacuum source.
 3. The enclosure of claim 2 comprising a tray located within the vacuum chamber and positioned to collect debris entrained through the work plate into the vacuum chamber.
 4. The enclosure of claim 3 in which: the inlet port is formed in a bottom wall of the vacuum chamber; the tray rests on the bottom wall and comprises an opening vertically aligned with the inlet port of the vacuum chamber; and, the filter seats against an upper surface of the tray and surrounds surrounds the opening in the tray.
 5. The enclosure of claim 4 in which: the work plate is associated with means releasably supporting the work plate in a predetermined position within the vacuum chamber; and, the filter is fastened to a bottom surface of the work plate and rests freely against the tray; whereby, the filter is removable with the work plate to allow access to the tray.
 6. The enclosure of claim 5 in which: the housing comprises a parallel pair of grooves that receive opposing sides of the tray for relative sliding movement along a predetermined axis; the housing comprises an access door positioned for sliding insertion and removal of the tray along the axis.
 7. The enclosure of claim 1 in which: the vacuum chamber has a bottom wall; the inlet port of the vacuum chamber is formed in the bottom wall; the vacuum source is located within the housing.
 8. The enclosure of claim 1 in which the access port comprises: an opening in the housing; closure means for at least partially closing the opening automatically after insertion or removal of an object through the opening.
 9. The enclosure of claim 9 in which the closure means comprise a flexible flap that restores elastically to rest position in which the flap is substantially coplanar with the opening and and deflects from the rest position in response to contact with an object.
 10. The enclosure of claim 8 in which the closure means comprise: an upper elastic flap fastened to the housing; a lower elastic flap fastened to the housing; each of the flaps biased by the elasticity of the flap to rest position in which the flap is substantially coplanar with the opening. 